Based on the data of Choi et al. [11], who characterized both long (ObRb) and short (ObRt) isoforms of leptin mRNA, as well as our previous study [14] showing protein expression of both isoforms of the leptin receptor in the immortalized OVCAR-3 ovarian cancer cell line, we used this cell line to analyze the effect of leptin on the expression of selected genes involved in the cell cycle and apoptosis. This evidence concerns the gene LEP and ovarian cancer.